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The Generalised Differential Image Motion Monitor (GDIMM) was proposed a few years ago as a new generation instrument for turbulence monitoring. It measures integrated parameters of the optical turbulence, i.e the seeing, isoplanatic angle,…

Instrumentation and Methods for Astrophysics · Physics 2020-12-18 Eric Aristidi , Yan Fantéï-Caujolle , Aziz Ziad , Julien Chabé , Christophe Giordano , Catherine Renaud , Alohotsy Rafalimanana

The performance of tomographic adaptive optics systems is intrinsically linked to the vertical profile of optical turbulence. Firstly, a sufficient number of discrete turbulent layers must be reconstructed to model the true continuous…

Instrumentation and Methods for Astrophysics · Physics 2020-04-08 O. J. D. Farley , J. Osborn , T. Morris , T. Fusco , B. Neichel , C. Correia , R. W. Wilson

Conventional ground-based astronomical observations suffer from image distortion due to atmospheric turbulence. This can be minimized by choosing suitable geographic locations or adaptive optical techniques, and avoided altogether by using…

Instrumentation and Methods for Astrophysics · Physics 2016-03-04 Peng Kian Tan , Aik Hui Chan , Christian Kurtsiefer

For high contrast imaging systems, the time delay is one of the major limiting factors for the performance of the extreme adaptive optics (AO) sub-system and, in turn, the final contrast. The time delay is due to the finite time needed to…

Instrumentation and Methods for Astrophysics · Physics 2019-04-08 Maaike van Kooten , Niek Doelman , Matthew Kenworthy

We present optical turbulence profiles obtained with a Generalized SCIDAR (G-SCIDAR) and a Low Layer SCIDAR (LOLAS) at the Observatorio Astron\'omico Nacional in San Pedro M\'artir (OAN-SPM), Baja California, Mexico, during three observing…

Instrumentation and Methods for Astrophysics · Physics 2019-11-12 R. Avila , O. Valdés-Hernández , L. J. Sánchez , I. Cruz-González , J. L. Avilés , J. J. Tapia-Rodríguez , C. A. Zúñiga

The estimation of atmospheric turbulence parameters is of relevance for: a) site evaluation & characterisation; b) prediction of the point spread function; c) live assessment of error budgets and optimisation of adaptive optics performance;…

Instrumentation and Methods for Astrophysics · Physics 2018-12-19 Paulo P. Andrade , Paulo J. V. Garcia , Carlos M. Correia , Johann Kolb , Maria Inês Carvalho

Atmospheric turbulence characterization is crucial for technologies like free-space optical communications. Existing methods using a spatially-integrated one-dimensional (1D) orbital angular momentum (OAM) spectrum, P(m), obscure the…

Optics · Physics 2025-09-09 Wenjie Jiang , Mingjian Cheng , Lixin Guo , Andrew Forbes

We present the Generalised Differential Image Motion Monitor. It is a compact instrument dedicated to measure 4 parameters of the optical turbulence: seeing, isoplanatic angle, coherence time and wavefront coherence outer scale. GDIMM is…

Instrumentation and Methods for Astrophysics · Physics 2019-04-16 E. Aristidi , A. Ziad , J. Chabe , Y. Fantei-Caujolle , C. Renaud , C. Giordano

Forecast of optical turbulence and atmospheric parameters relevant for ground-based astronomy is becoming an important goal for telescope planning and AO instruments optimization in several major telescope. Such detailed and accurate…

Instrumentation and Methods for Astrophysics · Physics 2022-10-21 A. Turchi , E. Masciadri , L. Fini

We discuss several improvements in the detection of atmospheric turbulence using SLOpe Detection And Ranging (SLODAR). Frequently, SLODAR observations have shown strong ground-layer turbulence, which is beneficial to adaptive optics. We…

Astrophysics · Physics 2009-11-13 Michael Goodwin , Charles Jenkins , Andrew Lambert

Atmospheric turbulence profile plays an important role in designing and operating adaptive optics (AO) systems with multiple laser guide stars. To obtain representative free atmospheric profiles and resolved ground layer profiles for future…

Instrumentation and Methods for Astrophysics · Physics 2023-10-17 Hajime Ogane , Yoshito Ono , Yosuke Minowa , Shin Oya , Koki Terao , Takumi Akasawa , Riki Homan , Masayuki Akiyama

Real-time seeing and outer scale estimation at the location of the focus of a telescope is fundamental for the adaptive optics systems dimensioning and performance prediction, as well as for the operational aspects of instruments. This…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Patrice Martinez

The efficiency of the management of top-class ground-based astronomical facilities supported by Adaptive Optics (AO) relies on our ability to forecast the optical turbulence (OT) and a set of relevant atmospheric parameters. Indeed, in…

Instrumentation and Methods for Astrophysics · Physics 2020-06-14 E. Masciadri , G. Martelloni , A. Turchi

The Profiler of Moon Limb is a recent instrument dedicated to the monitoring of optical turbulence profile of the atmosphere. Fluctuations of the Moon or the Sun limb allow to evaluate the index refraction structure constant C_n^2(h) and…

Instrumentation and Methods for Astrophysics · Physics 2020-02-13 Eric Aristidi , Aziz Ziad , Yan Fantéï-Caujolle , Julien Chabé , Christophe Giordano , Catherine Renaud , Henri Lantéri

We report the development and first results of an instrument called Low Layer Scidar (LOLAS) which is aimed at the measurement of optical-turbulence profiles in the atmospheric boundary layer with high altitude-resolution. The method is…

Astrophysics · Physics 2009-11-13 R. Avila , J. L. Aviles , R. W. Wilson , M. Chun , T. Butterley , E. Carrasco

We present a simple method of extracting a small number of reference optical turbulence and wind profiles from a large dataset for single conjugate and extreme adaptive optics simulations. These reference profiles can be used in slow…

Instrumentation and Methods for Astrophysics · Physics 2022-10-18 O. J. D. Farley

Atmospheric turbulence degrades the performance of free-space optical (FSO) communication and remote sensing systems by introducing phase and intensity distortions. While a majority of research focuses on mitigating these effects to ensure…

The next generation of adaptive optics (AO) systems will require tomographic reconstruction techniques to map the optical refractive index fluctuations, generated by the atmospheric turbulence, along the line of sight to the astronomical…

Instrumentation and Methods for Astrophysics · Physics 2014-01-07 H. W. Shepherd , J. Osborn , R. W. Wilson , T. Butterley , R. Avila , V. S. Dhillon , T. J. Morris

A characterization of the optical turbulence vertical distribution (Cn2 profiles) and all the main integrated astroclimatic parameters derived from the Cn2 and the wind speed profiles above the site of the Large Binocular Telescope (Mt.…

Instrumentation and Methods for Astrophysics · Physics 2010-11-29 E. Masciadri , J. Stoesz , S. Hagelin , F. Lascaux

We report the atmospheric turbulence parameters namely, atmospheric seeing, the tilt-anisoplanatic angle ($\theta_0$) and the coherence time ($\tau_0$), measured under various sky conditions, at Vainu Bappu Observatory in Kavalur. Bursts of…

Instrumentation and Methods for Astrophysics · Physics 2019-01-09 Sreekanth Reddy , Ravinder Kumar Banyal , Sridharan R , Aishwarya Selvaraj